Solid electrolytes with potassium cation conductivity in K1−2xMxAlO2 (M = Ba, Pb) systems

New solid electrolytes with high potassium cationic conductivity based on potassium monoaluminate were synthesized and studied in the K1−2xBaxAlO2 and K1−2xPbxAlO2 systems. A partial substitution of potassium cations with double charged positive cations results in a considerable increase in the conductivity of KAlO2 in the whole studied range of temperatures. The electric characteristics are somewhat higher in the bariumcontaining system, which is in all probability connected with the effect of the size factor: the size of the Ba2+ ion is higher than that of Pb2+, which must correlate with the increase of the effective dimensions of the migration channels in the electrolyte structure. The main cause of the conductivity increase at the introduction of the studied additives is the formation of potassium vacancies at the substitution of 2K+ → Ba2+(Pb2+) + V′K.